It happened Sunday at the end of "Marry Me" when Theodore "Teddy" Howell of Reading, a surgical tech with Coordinated Health, proposed to his girlfriend of 20 months, Maria Ramos, on Musikfest's main Steel Stage.

It was the first proposal Musikfest has ever had on its main stage in the festival's 31 years, ArtsQuest Public Relations Director Mark Demko said.

"We got a little special thing about to happen," Derulo told the crowd near the end of the song. Howell and Ramos walked to the side of the stage and he addressed her:

"Maria, ever since I met you, my whole life has changed. I just want to let you know that you complete me. And I would like to know … " He knelt and, with the crowd screams drowning him out, said, "Would you marry me?"

As Derulo finished the song, Howell placed an engagement ring on Ramos' finger.

"She said yes!" Derulo said. "Congratulations! I told you it was a special day."

Coordinated Health officials said it was a surprise to most everyone, including Ramos.

"I was very surprised," Ramos said in a video produced by Coordinated Health. "I thought we were going to go and take a picture or something, but I had no clue what was going on."

Hannah Ropp, a marketing representative for Coordinated Health, said they came up with the idea after learning Derulo had allowed a similar proposal on stage in the past. Ropp said they learned that Howell, who's been with the company almost five years and works in its Bethlehem hospital, was looking for a special way to propose.

Coordinated Health a month ago approached Musikfest about the proposal, Ropp said. Festival officials worked with Derulo's management. About two weeks ago, the idea got the tentative green light, and at 2 p.m. Sunday – about six hours before the concert – details were worked out.

Howell's cover story was to tell Ramos that Coordinated Health had arranged a meet-and-greet with Derulo. Right before the song, they were pulled on stage.

In the video, Howell said they met online and had a first date Dec. 15, 2012. "When I met her, I knew she was the one instantly," he said.

To mark the proposal, Coordinated Health erected an arch of helium-filled orange balloons above the Steel Stage crowd as a sort of wedding arch. It rose 1,200 feet in the air, making it the tallest structure in the Lehigh Valley. To go any higher would have required Federal Aviation Administration approval, O'Keefe said.